Typical portable audio devices (i.e., portable MP3 players, cassette players, and CD players) often include a set of headphones that connect to the device. As the headphone industry has progressed, numerous styles of headphones have become available. One of the more popular styles is the earbud style of headphones in which each earbud of the headset is designed to fit within the user's ear. The popularity of the earbud design is attributable to a host of factors, including the relative portability and small size of the earbuds.
Many earbuds consist of at least two parts which come together to form the earbud. The two parts are a base housing which holds the earphone speaker and a rear housing which contains the speaker within the assembled casing and allows the wire carrying the audio signal to be attached to the earphone.
One problem with this design is that if the joining strength of the base housing and rear housing is not strong enough, the two components may detach from one another when subjected to sufficient stress or impact. For example, a user may inadvertently step on the headphones, thus causing the housing components to detach. Another typical occurrence is that the headphones are dropped, which also may result in the rear and base housings coming apart. An earphone is usually used at eye level of a person typically between 1.5-1.8 m tall. However, some earbud casings tend to detach even when dropped from a much lower height of approximately 0.8-0.9 m. Most earphones detach when strained with an impact force of approximately 1.8-2 kg.
Conventional methods used to overcome these problems include the use of ultrasonic bonding or adhesives. In ultrasonic bonding, the base and rear housings are sealed using ultrasonic acoustic vibrations to create a solid-state weld. With adhesives, the housing components are glued together. In either method, the earphone casing is permanently sealed so that the parts of the housing do not detach when dropped. This permanent seal, however, makes the earphone components impossible to service without essentially breaking the unit. Accordingly, there is a need for earbud style headphones with improved resilience to stress that are easier to maintain in the event of detachment.